The PWM type DC/DC converter series for AC/DC provides an optimum system for all products that include an electrical outlet. It enables simpler design of a high effective converter specializing in non-isolated devices. This series has a built-in HV starter circuit that tolerates 650V, and it contributes to low power consumption. With a current detection resistor as internal device, it can be designed as small power supply. Since current mode control is utilized, current is restricted in each cycle and excellent performance is demonstrated in bandwidth and transient response. The switching frequency is fixed to 65 kHz. At light load, the switching frequency is reduced and high efficiency is achieved. A frequency hopping function is also on chip, and it contributes to low EMI. In addition, a built-in super junction MOSFET which tolerates 650V makes the design easy.